The need for the storage and retrieval of information in modern society is increasing at a rapid rate. In most computer-based information systems, bits of information are conventionally stored in magnetic memories. For example, magnetic tape and disc storage systems are in prevalent use with many types of computer systems ranging from main frame computers to home computers. In a magnetic memory, bits of information are magnetically stored or recorded on a magnetic recording medium.
Recently, optical storage and retrieval systems have been considered and proposed as alternatives or, at least, as supplements to the conventional magnetic storage systems. In conventional optical storage systems, bits of information are stored in various types of recording mediums and the bits of information are readable by light through different mechanisms, such as changes in reflectivity or polarization.
In accordance with the present invention, an optical storage device is provided which optically stores bits of information. The optical storage device in accordance with the present invention is extremely effective and has a wide range of applicability in optical storage and retrieval systems. Optical storage devices in accordance with the present invention may be designed to provide an erasable memory having a relatively fast switching time for recording and erasing bits of information.